Composite Wood Board

ABSTRACT

In a stack of composite wood boards, the wood boards comprise wood particles and an organic binder.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/915,968, filed Jun. 12, 2013, which is a continuation of U.S. patentapplication Ser. No. 12/524,522, filed Nov. 12, 2009 (now U.S. Pat. No.8,501,838), which is a U.S. national counterpart application ofInternational Application Ser. No. PCT/EP2007/050746, filed Jan. 25,2007, the entire disclosures of each of which are hereby incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to composite wood boards, for example particleboards, orientated strand boards and wood fibre boards, and particularlyto composite wood board comprising a bioresin and/or having a lowformaldehyde or formaldehyde free binder.

BACKGROUND

Bioresin is a term coined to describe a resin or resin formulationderived from a biological source. Thus, many traditional resins such asprotein-based soybean, collagen or casein, or carbohydrate-derivativesfrom cellulose or starch, natural rubber based adhesives and naturalphenolic adhesives such as tannin or lignin may all be classed asbioresins. They are renewable polymers and, with low environmentalimpact, represent an alternative to existing petroleum-driven systems.

Interest in bio-resin systems stems largely from increasing regulationand public concern for a pollution-free environment, and the need forsustainable alternatives to products based upon a finite petrochemicalresource. Commercial thermoset resin production and use is subject tosuch regulation largely due to the monomer components that form thebasis of the formulation. Overwhelmingly, these resins are based onmelamine, phenol, urea, formaldehyde, styrene or isocyanate startingmaterials.

Emissions of formaldehyde, phenol and isocyanate are generallyregulated; they are governed in England and Wales under the PollutionPrevention and Control Regulations (2000), SI19, for installationsinvolved in the manufacture of particleboard (PB), oriented strandboard(OSB), medium density fibreboard (MDF) and wood fibreboard. Emissions toair are limited to 5 mg/m³. In particular, the guidance notes that‘operators should use resins which minimise emissions of formaldehydewherever possible. The choice of resins used should be continuallyreviewed to ensure minimum emissions occur. Problems may existconcerning both high formaldehyde levels in the workplace and with theslow release of formaldehyde from the panel products themselves,particularly at the beginning of the product's lifetime.

Bioresin products may offer an alternative, renewable source ofthermosetting resins that will begin to address the depletion of finiteresources and have better emissions profiles, particularly whenformulated without formaldehyde. Though formaldehyde-free materials suchas iisocyanate and tannin resins have become available, about 85% of MDFproduced today uses formaldehyde resin, corresponding to a Europeanmarket of approximately 2 million tonnes per annum. In those resins,whilst a reduction in formaldehyde content has been achieved in recentyears, it has been at the cost of longer processing times, and decreasesin internal bond and bending strengths and an increase in swelling andwater absorption of panel products made therefrom. There is, thus, aclear place in the market now for new more environmentally friendlyresins that are competitive in price, performance and adaptable toexisting composite manufacturing processes.

SUMMARY

According to one aspect, the present invention provides a composite woodboard as defined in claim 1. Other aspects are defined in otherindependent claims. Preferred and/or alternative features are defined inthe dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting examples of laboratory scale tests relating to theinvention are described below with reference to the accompanyingdrawings of which:

FIG. 1 shows the cutting pattern for boards in Example 2;

FIG. 2 shows the effects of pressing times on IB for particle boardswith BS1 resin in Example 2;

FIG. 3 shows the effects on pressing times on IB for particle boardswith BS1-SOK resin in Example 2;

FIG. 4 shows thickness swelling after 24 hours at 20° C. in relation toExample 2;

FIG. 5 shows water absorption swelling after 24 hours at 20° C. inrelation to Example 2;

FIG. 6 shows effects of pressing times on IB for orientated strand boardwith BS1 resin in relation to Example 2;

FIG. 7 shows a number of illustrative reactants for producingmelanoidins; and

FIG. 8 illustrates a Maillard reaction schematic when reacting areducing sugar with an amino compound.

DETAILED DESCRIPTION

The composite wood board is preferably an industrially manufacturedcomposite wood board, as opposed to a laboratory test manufactured woodboard. The composite wood board may have dimensions of at least30cm×30cm; it may have dimensions of at least 50 cm×80 cm, possibly atleast 1 m×2m.

The composite wood board may have edges which are trimmed and/or cutand/or machined.

The composite wood board may be provided as a package comprises aplurality or wood boards arranged and/or bound together, for example tofacilitate transport; it may comprise an enveloping film, for example ofa plastics material. The package may comprise a pallet; it may beadapted by handling by mechanical lifting equipment and/or a fork lifttruck.

The composite board may have a nominal thickness of at least 11 mm, atleast 12 mm or at least mm.

The curing time of the composite wood board is preferably less than 25minutes. The binder may:

-   -   be based on a reducing sugar; and/or    -   be based on reductosis; and/or    -   be based on an aldehyde containing sugars; and/or    -   include at least one reaction product of a carbohydrate reactant        and an amine reactant; and/or    -   include at least one reaction product of a reducing sugar and an        amine reactant; and/or    -   include at least one reaction product of a carbohydrate reactant        and a polycarboxylic acid ammonium salt reactant; and/or    -   include at least one reaction product from a Maillard reaction.

EXAMPLE 1a

Preparation of Ammonium polycarboxylate-Sugar Binders Used to ConstructWood Fiber Board Compositions

Aqueous triammonium citrate-dextrose (1:6) binders were prepared by thefollowing general procedure: Powdered dextrose monohydrate (915 g) andpowdered anhydrous citric acid (152.5 g) were combined in a 1-gallonreaction vessel to which 880 g of distilled water was added. To thismixture were added 265 g of 19% aqueous ammonia with agitation, andagitation was continued for several minutes to achieve completedissolution of solids. To the resulting solution were added 3.3 g ofSILQUEST A-1101 silane to produce a pH ˜8-9 solution (using pH paper),which solution contained approximately 50% dissolved dextrosemonohydrate and dissolved ammonium citrate solids (as a percentage oftotal weight of solution); a 2-g sample of this solution, upon thermalcuring at 400° F. for 30 minutes, would yield 30% solids (the weightloss being attributed to dehydration during thermoset binder formation).Where a silane other than SILQUEST A-1101 was included in thetriammonium citrate-dextrose (1:6) binder, substitutions were made withSILQUEST A-187 Silane, HYDROSIL 2627 Silane, or Z-6020 Silane. Whenadditives were included in the triammonium citrate-dextrose (1:6) binderto produce binder variants, the standard solution was distributed amongbottles in 300-g aliquots to which individual additives were thensupplied.

When polycarboxylic acids other than citric acid, sugars other thandextrose, and/or additives were used to prepare aqueous ammoniumpolycarboxylate sugar binder variants, the same general procedure wasused as that described above for preparation of an aqueous triammoniumcitrate-dextrose (1:6) binder. For ammonium polycarboxylate-sugar bindervariants, adjustments were made as necessary to accommodate theinclusion of, for example, a dicarboxylic acid or a polymericpolycarboxylic acid instead of citric acid, or to accommodate theinclusion of, for example, a triose instead of dextrose, or toaccommodate the inclusion of, for example, one or more additives. Suchadjustments included, for example, adjusting the volume of aqueousammonia necessary to generate the ammonium salt, adjusting the gramamounts of reactants necessary to achieve a desired molar ratio ofammonium polycarboxylate to sugar, and/or including an additive in adesired weight percent.

Several methods were used to produce wood fiber boards/sheets bondedwith this triammonium citrate-dextrose (1:6) binder. A representativemethod, which method produced strong, uniform samples, is as follows:Wood in the form of assorted pine wood shavings and sawdust waspurchased from a local farm supply store. Wood fiber board samples weremade with the as received wood and also material segregated into theshavings and sawdust components. Wood was first dried in an oven atapproximately 200° F. overnight, which drying resulted in moistureremoval of 14-15% for the wood shavings and about 11% for the sawdust.Thereafter, dried wood was placed in an 8 inch high×12 inch wide×10.5inch deep plastic container (approximate dimensions). Triammoniumcitrate-dextrose (1:6) binder was prepared (36% in binder solids) asdescribed above, and then 160 g of binder was sprayed via an hydraulicnozzle onto a 400-g sample of wood in the plastic container while thecontainer was inclined 30-40 degrees from the vertical and rotatedslowly (approximately 5-15 rpm). During this treatment, the wood wasgently tumbled while becoming uniformly coated.

Samples of resinated wood were placed in a collapsible frame andcompressed in between heated platens under the following conditions:resinated wood shavings, 300 psi; resinated sawdust, 600 psi. For eachresinated sample, the cure conditions were 350° F. for 25 to 30 minutes.The resulting sample boards were approximately 10 inches long×10 incheswide, and about 0.4 inches thick before trimming, well-bondedinternally, smooth surfaced and made a clean cut when trimmed on theband saw. Trimmed sample density and the size of each trimmed sampleboard produced were as follows: sample board from wood shavings, density˜54 pcf, size ˜8.3 inches long×9 inches wide×0.36 inches thick; sampleboard from sawdust, density ˜44 pcf, size ˜8.7 inches long×8.8 incheswide×0.41 inches thick. The estimated binder content of each sampleboard was ˜12.6%.

EXAMPLE 1b

The following samples were tested to compare the Flexural and Tensilestrength of standard particle board and oriented strand board withsimilar products made using a new test binder:

Commercially available ½ in. particle board purchased from BuildersLumber Commercially available ½ in. oriented strand board (OSB)purchased from Builders Lumber Test wood particle board made asdescribed above 8.75 × 8.87 × 0.414 371.9 gm. 44.1 lbs/ft³ 12.6% binderTest wood shavings board made as described above 8.37 × 9 × 0.336 361.2gm. 54.4 lbs/ft³ 12.6% binder

The test boards were each approximately 8 ¾ inches square. The boardsfrom builders were approximately 2 ft×4 ft when purchased. These boardswere cut down to approximately 8 ¾ inches square so that the sampleswould be collected consistently from the various products.

The test results are set out in tables 1 to 5:

TABLE 1 Summary results Tensile Strength Flexural Strength Max TensileLoad @ Thickness Density Load Strength Thickness Density break ModulusIn. Lb/ft³ lbs psi In. Lb/ft³ lbs psi Particle board 0.521 41.36 296.95760.70 0.520 45.81 76.26 325295.1 (store bought) Test-Particle 0.41642.82 270.55 868.44 0.445 45.05 61.38 281499.6 board Oriented strand0.463 36.66 293.92 848.92 0.495 37.05 87.82 293246.4 board (storebought) Test-Oriented 0.331 51.64 274.20 1124.94 0.386 50.67 77.02322299.0 strand board

TABLE 2 Detail Data - Standard Particle Board (store bought) FlexuralStrength Tensile Strength Load Max Tensile @ Particle Thickness DensityLoad Strength Thickness Density break Modulus Board In. Lb/ft³ lbs psiIn. Lb/ft³ lbs psi 1 0.520 41.45 307.63 788.80 0.523 46.68 78.45301254.6 2 0.521 41.35 286.26 732.60 0.521 46.93 78.95 313865.3 3 0.52046.64 73.80 314028.9 4 0.522 45.04 71.87 335869.0 5 0.518 44.47 76.23340901.5 6 0.516 45.08 78.24 345851.6

TABLE 3 Detail Data - Test Particle Board Flexural Strength TensileStrength Test Max Tensile Load @ Particle Thickness Density LoadStrength Thickness Density break Modulus Board In. Lb/ft³ lbs psi In.Lb/ft³ lbs psi 1 0.416 40.99 204.30 654.82 0.418 51.02 75.88 316852.8 20.415 44.76 336.79 1082.06 0.431 49.89 72.45 329690.9 3 0.441 41.7256.33 247006.3 4 0.450 47.66 68.94 348970.7 5 0.463 44.37 59.02 281044.96 0.468 35.62 35.62 165461.8

TABLE 4 Detail Data - Standard Oriented Strand Board (store bought)Flexural Strength Tensile Strength Load Oriented Max Tensile @ strandThickness Density Load Strength Thickness Density break Modulus boardIn. Lb/ft³ lbs psi In. Lb/ft³ lbs psi 1 0.468 36.47 250.98 715.03 0.47538.67 41.02 177706.4 2 0.457 36.91 336.86 982.81 0.512 36.03 79.96230090.1 3 0.495 36.57 52.95 198956.0 4 0.491 37.88 126.31 412893.2 50.495 36.45 115.87 375834.9 6 0.500 36.68 110.82 363997.5

TABLE 5 Detail Data - Test Oriented Strand Board Tensile StrengthFlexural Strength Test Max Tensile Load @ oriented Thickness DensityLoad Strength Thickness Density break Modulus strand board In. Lb/ft³lbs psi In. Lb/ft³ lbs psi 1 0.317 54.39 382.26 1607.84 0.351 56.5753.61 241391.0 2 0.345 49.10 166.13 642.04 0.380 54.20 78.17 363683.1 30.400 51.12 81.74 365485.3 4 0.384 53.08 91.70 402491.0 5 0.400 46.7289.90 338210.5 6 0.400 42.34 67.00 222533.0

EXAMPLE 2

Two experimental resins were used, BS1 and BS1-SOK (solids content of50%). Particle boards (PB), oriented strand boards (OSB) and mediumdensity fibreboards (MDF) were manufactured with those two resinsystems.

Manufacture of Test Particle Boards:

Single layer particleboards were manufactured. Wood chips for themanufacture of the particleboards were for commercial particleboardmanufacture, these chips would have consisted of a mixture of woodspecies and was thought to consist mainly of recycled timber. Prior touse the chips were sieved to remove oversize material and shives. Beforeresination, the chips were dried to constant moisture content (MC).Hereinafter, moisture content will be expressed as the weight of watercontained in wood as a percentage of the oven dry weight of wood.

12% or 14% resin was added to the wood chips (weight of resin solids toweight of dry wood). The resin and chips were blended together in aKenwood or Drum blender. The dry chip moisture content and the moisturecontent of the sprayed chips were all measured; the information issummarised in Table 6. The mass of chips per board was adjustedaccording to moisture content in order to achieve a target density of650 kg/m³.

After blending the resin, additives and chips, the resultant “furnish”was transferred to a forming box and lightly compacted before being hotpressed for final consolidation and resin curing.

Boards were pressed using a target platen temperature of 220° C. and atotal press time of 5-12 minutes. Panels were 500 mm by 500 mm or 300 mmby 300 mm square and 12 mm thick. On removal from the hot press theboards were labelled and after cooling the edges were trimmed.

Manufacture of Test Orientated Strand Boards:

The flakes are sifted and separated into core and surface flakes. Largesize flakes are used in surface layers, small size in core layer.

The surface material is blended with 14% BS1 resin (resin to timber, drybasis) and water in two benders. Resin is mixed with water through astatic mixer. Water is added to reduce the viscosity of the resin andincrease the flake MC to 12%.

The core material is blended with 12% BS1 resin and water in a singlebender. Target core flake MC is at 10-12%.

The blended material is conveyed to three forming stations, surface,core and surface. The surface formers align the flakes parallel to themachine direction, whilst the core former arranges the flakesperpendicular to the machine direction. Flake alignment is achieved by aseries of paddles or rollers in the forming stations.

The boards information was shown in table 7. PB-1 to PB-11 were madewith B S1 resin, PB12 to PB14 made with BS1-SOK resin.

TABLE 6 Particle boards information Resin Moisture content, % Processing Loading, Post- Temp, Time, Addi- Type % Pre-blend blend ° C.min tives PB-1 BS1 12 3.22 12.1 220 5 No PB-2 BS1 12 4.24 12.26 220 9 NoPB-3 BS1 12 3.22 12.1 220 10 No PB-4 BS1 12 3.54 12.32 220 10 No PB-5BS1 12 3.54 12.32 220 10 No PB-6 BS1 12 4.78 12.27 220 10 No PB-7 BS1 123.36 12.25 220 10 No PB-8 BS1 12 4.24 12.92 220 10 No PB-9 BS1 12 4.2412.92 220 10 No PB-10 BS1 12 3.78 11.8 220 10 Wax PB-11 BS1 14 3.22 12220 10 No PB-12 BS1-SOK 12 3.68 15.68 220 5 No PB-13 BS1-SOK 12 3.6814.44 220 9 No PB-14 BS1-SOK 12 3.47 12.86 220 10 No

TABLE 7 Oriented strand boards information Moisture content, %Processing Pre- Post- Temp, Time, blend blend º C. min OSB-1 Surface4.84 12.1 220 9 Core 5.39 11.65 OSB-2 Surface 2.84 11.21 220 10 Core2.86 10.03 OSB-3 Surface 3.71 12.04 220 12 Core 3.56 11.37 OSB-4 Surface3.22 9.89 220 15 Core 3.22 8.23

Manufacture of Test Medium Density Fibreboards:

A standard raw material was used: chipped softwood (primarily spruce)obtained from Kronospan.

12% BSI resin was added to the MDF (weight of resin solids to weight ofdry fibres). The MC before and post blend was 8.26 and 16.23%,respectively.

Boards were pressed using a target platen temperature of 220° C. and atotal press time of 10 minutes.

Preparation of Samples for Testing:

After cooling each board was cut to a specified pattern, see FIG. 1 fordetails. The sample size (from positions 1-12) was 50 mm by 50 mmsquares, sample width from positions 13 and 14 was 50 mm.

From each board six samples (from positions 1, 3, 5, 8, 10 and 12) weretested for internal bond strength in accordance with EN319, six (frompositions 2, 4, 6, 7, 9 and 11) for thickness swelling and waterabsorption with EN317. Two from positions 13 and 14 were tested formodulus of elasticity in bending and of bending strength according toEN310.

Testing:

Internal Bond Strength

-   -   Transverse Internal Bond Strength. (EN 319 for PB and EN 300 for        OSB)

Moisture absorption & thickness swelling

-   -   Thickness Swelling after 24 hrs in Water at 20° C. (EN 317)    -   Water Absorption after 24 hrs in Water at 20° C.

Modulus of elasticity in bending and of bending strength.

-   -   Modulus of elasticity (MOE), (EN 310)    -   Bending strength (MOR)

Test results for particle boards:

Table 8 summarises the results for internal bond strength (IB) ofparticle boards.

FIGS. 2 and 3 show the effects of pressing times on IB. It was notedthat PB-3 to PB-9 shared the same processing (temperature and times) andIB varied within error, so the average at 0.43 N/mm² with STD 0.03 wasincluded in FIG. 2 . The general requirement of 0.4 N/mm² for IB fromstandards was also indicated in FIGS. 2 and 3 .

It was apparent that resins in PB-I and PB-12 pressed for 5 min haddeveloped no significant bond strengths due to insufficient press times,bond strengths were improved when increased the pressing times to 9 min(PB-2 and PB-13), bond strength over standard value was obtained for PBwith BS1 resin (PB-3 to PB-9) when further increased the pressing timesto 10 min. However, with BS1-SOK resin system, IB (PB14) was lower thanthe standard requirement.

For PB-10, Wax was added in, it seems there was no significant effectson IB. IB for PB-11 which had a resin loading at 14%, 2% higher than therest boards, was 0.5 N/mm². This suggested that the increase of resinloading will increase the bond strengths.

TABLE 8 Internal bond strength of panels Density, Kg/m3 STD IB, N/mm2STD PB-1 552 22.2 0.02 0.01 PB-2 598 18.75 0.37 0.02 PB-3 565 12.9 0.460.02 PB-4 617 10.5 0.46 0.03 PB-5 592 8.3 0.44 0.02 PB-6 591 6.9 0.430.04 PB-7 610 15.8 0.41 0.05 PB-8 615 23.4 0.46 0.04 PB-9 613 39.4 0.400.07 PB-10 630 20.6 0.47 0.05 PB-11 617 6.04 0.5  0.03 PB-12 638 37.60.05 0.02 PB-13 627 8.9 0.25 0.06 PB-14 567 12.1 0.35 0.05

The results of the tests for thickness swelling and water absorption aresummarised in FIGS. 4 and 5 .

PB-8, 9 and 10 were processed at same temperature and times, the onlydifference between PB-8, 9 and 10 was the addition of wax, 0.8% wax wasadded in PB-10.

There were no significant differences on thickness swelling and waterabsorption between PB-8 and PB-9, both thickness swelling and waterabsorption were much higher than the requirement by standard, asindicated by solid line in FIG. 6 . Significant difference were apparentin addition of wax, sample had the lowest thickness swelling and waterabsorption, which also was lower than the requirement by standard. Thissuggested that use of wax helped to improve thickness swelling and waterabsorption.

Modulus of Elasticity in Bending and of Bending Strength

Only the boards (PB-8 and PB-9) made at 220° C. for 10 min were testedfor modulus of elasticity and bending strength. The average for MOE was2314 N/mm² with STD of 257.68, which was much higher than therequirement by standard of 1800 N/mm². This means the board was muchstiffer. Average for MOR was 10.4 N/mm², which was lower than therequirement of 14 N/mm². To improve MOR to match the requirement,increasing the resin loading may be the right way.

Results for Oriented Strand Boards (OSB)

FIG. 6 summarises the results for internal bond of oriented strandboard, the solid line indicated the requirement of 0.28 N/mm² bystandard (EN300) for OSB.

IB was always lower than the requirement; to improve the bond strengthfor OSB boards with BS1 resin, the processing parameters and/or theresin loading should be considered.

Modulus of Elasticity in Bending and of Bending Strength

Boards OSB-2 and OBS-3 were tested for MOR and MOE, the results aresummarized in table 9. The requirements by standard were 18 N/mm² and2500 N/mm². Both OSB-2 and OSB-3 had much higher MOR and MOE than therequirements for general purpose boards, though the IB was lower. Notonly the bonding strength between fibres and resin but also the fibredimension and orientation would be of benefit to MOR and MOE.

The current values also were greater than the requirements for loadbearing boards for use in both dry and humid conditions which are 20N/mm² and 3500 N/mm², however, lower than the requirement for heavy dutyload bearing boards 28 N/mm² and 4800 N/mm².

TABLE 9 MOR and MOE results for OSB MOR, N/mm2 STD MOE, N/mm2 STD OSB-226.47 4.11 4158.0 564.58 OSB-3 24.89 2.42 3861.9 428.73

Results for Medium Density Board Internal Bond Strength

Only one trial of medium density board was manifested. The pressingtemperature was 220° C. and time was 10 min. The average of IB was 0.43N/mm² with STD at 0.03, which was higher than the requirement of 0.4N/mm² by standard.

Modulus of Elasticity in Bending and of Bending Strength

The average for MOR was 22.26 N/mm² with STD of 1.31, which was 60%higher than the requirement by standard of 14 N/mm². Average for MOE was2771.62 N/mm² STD 204.17 which was over 50% greater than the requirementof 1800 N/mm².

Note that 14 N/mm² and 1800 N/mm² are the requirement for generalpurpose boards of use in dry condition. The requirements forload-bearing boards of use in dry or humid conditions are 18 N/mm² and2500 N/mm², IB of 0.45 N/mm². The current MOR and MOE were greater thanthis requirements as well though IB was slighter lower. However, withthe optimisation of processing, MDF must achieve all the requirementsfor load-bearing boards or even for heavy duty load bearing ones.

Discussion of Results from Example 2:

The pressing times and resin loading played an important role in IB ofparticle boards made with BS1 resin, IB increased with the increase ofpressing times and resin loading. However, for particle boards made withBS1-SOK resin, IB varied with the increase of pressing time, and whichwas always lower than the requirement by standard. Optimisation ofprocess parameters would be expected to lead to improvements.

Thickness swelling and water absorption was improved by the addition ofwax in particle board, the values were lower than the requirement bystandard. Optimisation should bring improvements.

Oriented strand boards made by BS1 resin had lower IB but higher MOR andMOE than the requirements by standards. IB strongly depended on thebonding strength between fibres and matrix, however, MOR and MOE wouldbe benefited from the fibre dimension and orientation.

By using BS1 resin, medium density fibre boards showed greatermechanical properties than the requirements of general purposes boards,with possibility to achieve the requirements for load-bearing boards byoptimising the processing.

The problem for oriented strand boards with BS1 resin is lower IB, toimprove this, increasing resin loading may be the right way forward.

Medium density boards with BS1 resin showed great performance;optimisation of the processing may meet the requirements forload-bearing boards or even heavy duty load bearing boards.

Whilst particular binders have been used in the examples, other bindersparticularly binders which are discussed below, may be used in thecontext of the invention.

Discussion of Binders:

Cured or uncured binders useful in connection with the present inventionmay comprise one or more of the following features or combinationsthereof. In addition, materials in accordance with the present inventionmay comprise one or more of the following features or combinationsthereof:

Initially it should be appreciated that the binders may be utilized in avariety of fabrication applications to produce or promote cohesion in acollection of non or loosely assembled matter. A collection includes twoor more components. The binders produce or promote cohesion in at leasttwo of the components of the collection. For example, subject bindersare capable of holding a collection of matter together such that thematter adheres in a manner to resist separation. The binders describedherein can be utilized in the fabrication of any material.

One potential feature of the present binders is that they areformaldehyde free. Accordingly, the materials the binders are disposedupon may also be formaldehyde free. In addition, the present binders mayhave a reduced trimethylamine content as compared to other knownbinders. With respect to the present binder's chemical constituents,they may include ester and/or polyester compounds. The binders mayinclude ester and/or polyester compounds in combination with a vegetableoil, such as soybean oil. Furthermore, the binders may include esterand/or polyester compounds in combination with sodium salts of organicacids. The binders may include sodium salts of inorganic acids. Thebinders may also include potassium salts of organic acids. Moreover, thebinders may include potassium salts of inorganic acids. The describedbinders may include ester and/or polyester compounds in combination witha clay additive, such as montmorillonite.

Furthermore, the binders of the present invention may include a productof a Maillard reaction. For example, see FIG. 8 . As shown in FIG. 8 ,Maillard reactions produce melanoidins, i.e., high molecular weight,furan ring and nitrogen-containing polymers that vary in structuredepending on the reactants and conditions of their preparation.Melanoidins display a C:N ratio, degree of unsaturation, and chemicalaromaticity that increase with temperature and time of heating. (See,Ames, J. M. in The Maillard Browning Reaction—an update, Chemistry andIndustry (Great Britain), 1988, 7, 558-561, the disclosure of which ishereby incorporated herein by reference). Accordingly, the subjectbinders may be made via a Maillard reaction and thus containmelanoidins. It should be appreciated that the subject binders maycontain melanoidins, or other Maillard reaction products, which productsare generated by a separate process and then simply added to thecomposition that makes up the binder. The melanoidins in the binder maybe water insoluble. Moreover, the binders may be thermoset binders.

The Maillard reactants to produce a melanoidin may include an aminereactant reacted with a reducing-sugar carbohydrate reactant. Forexample, an ammonium salt of a monomeric polycarboxylic acid may bereacted with (i) a monosaccharide in its aldose or ketose form or (ii) apolysaccharide or (iii) with combinations thereof. In another variation,an ammonium salt of a polymeric polycarboxylic acid may be contactedwith (i) a monosaccharide in its aldose or ketose form or (ii) apolysaccharide, or (iii) with combinations thereof In yet anothervariation, an amino acid may be contacted with (i) a monosaccharide inits aldose or ketose form, or (ii) with a polysaccharide or (iii) withcombinations thereof. Furthermore, a peptide may be contacted with (i) amonosaccharide in its aldose or ketose form or (ii) with apolysaccharide or (iii) with combinations thereof. Moreover, a proteinmay be contacted with (i) a monosaccharide in its aldose or ketose formor (ii) with a polysaccharide or (iii) with combinations thereof.

It should also be appreciated that the binders may include melanoidinsproduced in non-sugar variants of Maillard reactions. In these reactionsan amine reactant is contacted with a non-carbohydrate carbonylreactant. In one illustrative variation, an ammonium salt of a monomericpolycarboxylic acid is contacted with a non-carbohydrate carbonylreactant such as, pyruvaldehyde, acetaldehyde, crotonaldehyde,2-furaldehyde, quinone, ascorbic acid, or the like, or with combinationsthereof. In another variation, an ammonium salt of a polymericpolycarboxylic acid may be contacted with a non-carbohydrate carbonylreactant such as, pyruvaldehyde, acetaldehyde, crotonaldehyde,2-furaldehyde, quinone, ascorbic acid, or the like, or with combinationsthereof. In yet another illustrative variation, an amino acid may becontacted with a non-carbohydrate carbonyl reactant such as,pyruvaldehyde, acetaldehyde, crotonaldehyde, 2-furaldehyde, quinone,ascorbic acid, or the like, or with combinations thereof. In anotherillustrative variation, a peptide may be contacted with anon-carbohydrate carbonyl reactant such as, pyruvaldehyde, acetaldehyde,crotonaldehyde, 2-furaldehyde, quinone, ascorbic acid, or the like, orwith combinations thereof In still another illustrative variation, aprotein may contacted with a non-carbohydrate carbonyl reactant such as,pyruvaldehyde, acetaldehyde, crotonaldehyde, 2-furaldehyde, quinone,ascorbic acid, and the like, or with combinations thereof.

The melanoidins discussed herein may be generated from melanoidinreactant compounds. These reactant compounds are disposed in an aqueoussolution at an alkaline pH and therefore are not corrosive. That is, thealkaline solution prevents or inhibits the eating or wearing away of asubstance, such as metal, caused by chemical decomposition brought aboutby, for example, an acid. The reactant compounds may include areducing-sugar carbohydrate reactant and an amine reactant. In addition,the reactant compounds may include a non-carbohydrate carbonyl reactantand an amine reactant.

It should also be understood that the binders described herein may bemade from melanoidin reactant compounds themselves. That is, once theMaillard reactants are mixed, this mixture can function as a binder ofthe present invention. These binders may be utilized to fabricateuncured, formaldehyde-free matter, such as fibrous materials.

In the alternative, a binder made from the reactants of a Maillardreaction may be cured. These binders may be used to fabricate curedformaldehyde free matter, such as, fibrous compositions. Thesecompositions are water-resistant and, as indicated above, includewater-insoluble melanoidins.

It should be appreciated that the binders described herein may be usedin manufacturing products from a collection of non or loosely assembledmatter. For example, these binders may be employed to fabricate fiberproducts. In one illustrative embodiment, the binders are used to makecellulosic compositions. With respect to cellulosic compositions, thebinders may be used to bind cellulosic matter to fabricate, for example,wood fiber board which has desirable physical properties (e.g.,mechanical strength).

One embodiment of the invention is directed to a method formanufacturing products from a collection of non-or loosely assembledmatter. The method may include contacting the fibers with athermally-curable, aqueous binder. The binder may include (i) anammonium salt of a polycarboxylic acid reactant and (ii) areducing-sugar carbohydrate reactant. These two reactants are melanoidinreactants (i.e., these reactants produce melanoidins when reacted underconditions to initiate a Maillard reaction.) The method can furtherinclude removing water from the binder in contact with the fibers (i.e.,the binder is dehydrated). The method can also include curing the binderin contact with the fibers (e.g., thermally curing the binder).

An example of utilizing this method is in the fabrication of cellulosicmaterials. The method may include contacting the cellulosic material(e.g., cellulose fibers) with a thermally-curable, aqueous binder. Thebinder may include (i) an ammonium salt of a polycarboxylic acidreactant and (ii) a reducing-sugar carbohydrate reactant. As indicatedabove, these two reactants are melanoidin reactant compounds. The methodcan also include removing water from the binder in contact with thecellulosic material. As before, the method can also include curing thebinder (e.g., thermal curing).

A fibrous product is described that includes a binder in contact withcellulose fibers, such as those in a mat of wood shavings or sawdust.The mat may be processed to form one of several types of wood fiberboard products. In one variation, the binder is uncured. In thisvariation, the uncured binder may function to hold the cellulosic fiberstogether. In the alternative, the cured binder may function to hold thecellulosic fibers together.

As used herein, the phrase “formaldehyde-free” means that a binder or amaterial that incorporates a binder liberates less than about 1 ppmformaldehyde as a result of drying and/or curing. The 1 ppm is based onthe weight of sample being measured for formaldehyde release.

Cured indicates that the binder has been exposed to conditions to so asto initiate a chemical change. Examples of these chemical changesinclude, but are not limited to, (i) covalent bonding, (ii) hydrogenbonding of binder components, and chemically cross-linking the polymersand/or oligomers in the binder. These changes may increase the binder'sdurability and solvent resistance as compared to the uncured binder.Curing a binder may result in the formation of a thermoset material.Furthermore, curing may include the generation of melanoidins. Thesemelanoidins may be generated from a Maillard reaction from melanoidinreactant compounds. In addition, a cured binder may result in anincrease in adhesion between the matter in a collection as compared toan uncured binder. Curing can be initiated by, for example, heat,electromagnetic radiation or, electron beams.

In a situation where the chemical change in the binder results in therelease of water, e.g., polymerization and cross-linking, a cure can bedetermined by the amount of water released above that would occur fromdrying alone. The techniques used to measure the amount of waterreleased during drying as compared to when a binder is cured, are wellknown in the art.

In accordance with the above paragraph, an uncured binder is one thathas not been cured.

As used herein, the term “alkaline” indicates a solution having a pHthat is greater than or equal to about 7. For example, the pH of thesolution can be less than or equal to about 10. In addition, thesolution may have a pH from about 7 to about 10, or from about 8 toabout 10, or from about 9 to about 10.

As used herein, the term “ammonium” includes, but is not limited to,^(+NH) ₄, ⁺NH₃R¹, and ^(+NH) ₂R¹R², where R¹ and R² are eachindependently selected in ^(+NH) ₂R¹R², and where R¹ and R² are selectedfrom alkyl, cycloalkyl, alkenyl, cycloalkenyl, heterocyclyl, aryl, andheteroaryl.

The term “alkyl” refers to a saturated monovalent chain of carbon atoms,which may be optionally branched; the term cycloalkyl refers to amonovalent chain of carbon atoms, a portion of which forms a ring; theterm alkenyl refers to an unsaturated monovalent chain of carbon atomsincluding at least one double bond, which may be optionally branched;the term cycloalkenyl refers to an unsaturated monovalent chain ofcarbon atoms, a portion of which forms a ring; the term heterocyclylrefers to a monovalent chain of carbon and heteroatoms, wherein theheteroatoms are selected from nitrogen, oxygen, and sulfur, a portion ofwhich, including at least one heteroatom, form a ring; the term arylrefers to an aromatic mono or polycyclic ring of carbon atoms, such asphenyl, naphthyl, and the like; and the term heteroaryl refers to anaromatic mono or polycyclic ring of carbon atoms and at least oneheteroatom selected from nitrogen, oxygen, and sulfur, such aspyridinyl, pyrimidinyl, indolyl, benzoxazolyl, and the like. It is to beunderstood that each of alkyl, cycloalkyl, alkenyl, cycloalkenyl, andheterocyclyl may be optionally substituted with independently selectedgroups such as alkyl, haloalkyl, hydroxyalkyl, aminoalkyl, carboxylicacid and derivatives thereof, including esters, amides, and nitriles,hydroxy, alkoxy, acyloxy, amino, alkyl and dialkylamino, acylamino,thio, and the like, and combinations thereof. It is further to beunderstood that each of aryl and heteroaryl may be optionallysubstituted with one or more independently selected substituents, suchas halo, hydroxy, amino, alkyl or dialkylamino, alkoxy, alkylsulfonyl,cyano, nitro, and the like.

As used herein, the term “polycarboxylic acid” indicates a dicarboxylic,tricarboxylic, tetracarboxylic, pentacarboxylic, and like monomericpolycarboxylic acids, and anhydrides, and combinations thereof, as wellas polymeric polycarboxylic acids, anhydrides, copolymers, andcombinations thereof. In one aspect, the polycarboxylic acid ammoniumsalt reactant is sufficiently non-volatile to maximize its ability toremain available for reaction with the carbohydrate reactant of aMaillard reaction (discussed below). In another aspect, thepolycarboxylic acid ammonium salt reactant may be substituted with otherchemical functional groups. Illustratively, a monomeric polycarboxylicacid may be a dicarboxylic acid, including, but not limited to,unsaturated aliphatic dicarboxylic acids, saturated aliphaticdicarboxylic acids, aromatic dicarboxylic acids, unsaturated cyclicdicarboxylic acids, saturated cyclic dicarboxylic acids,hydroxy-substituted derivatives thereof, and the like. Or,illustratively, the polycarboxylic acid(s) itself may be a tricarboxylicacid, including, but not limited to, unsaturated aliphatic tricarboxylicacids, saturated aliphatic tricarboxylic acids, aromatic tricarboxylicacids, unsaturated cyclic tricarboxylic acids, saturated cyclictricarboxylic acids, hydroxy-substituted derivatives thereof, and thelike. It is appreciated that any such polycarboxylic acids may beoptionally substituted, such as with hydroxy, halo, alkyl, alkoxy, andthe like. In one variation, the polycarboxylic acid is the saturatedaliphatic tricarboxylic acid, citric acid. Other suitable polycarboxylicacids are contemplated to include, but are not limited to, aconiticacid, adipic acid, azelaic acid, butane tetracarboxylic acid dihydride,butane tricarboxylic acid, chlorendic acid, citraconic acid,dicyclopentadiene-maleic acid adducts, diethylenetriamine pentaaceticacid, adducts of dipentene and maleic acid, ethylenediamine tetraaceticacid (EDTA), fully maleated rosin, maleated tall-oil fatty acids,fumaric acid, glutaric acid, isophthalic acid, itaconic acid, maleatedrosin oxidized with potassium peroxide to alcohol then carboxylic acid,maleic acid, malic acid, mesaconic acid, biphenol A or bisphenol Freacted via the KOLBE-Schmidt reaction with carbon dioxide to introduce3-4 carboxyl groups, oxalic acid, phthalic acid, sebacic acid, succinicacid, tartaric acid, terephthalic acid, tetrabromophthalic acid,tetrachlorophthalic acid, tetrahydrophthalic acid, trimellitic acid,trimesic acid, and the like, and anhydrides, and combinations thereof.

Illustratively, a polymeric polycarboxylic acid may be an acid, forexample, polyacrylic acid, polymethacrylic acid, polymaleic acid, andlike polymeric polycarboxylic acids, copolymers thereof, anhydridesthereof, and mixtures thereof. Examples of commercially availablepolyacrylic acids include AQUASET-529 (Rohm & Haas, Philadelphia, Pa.,USA), CRITERION 2000 (Kemira, Helsinki, Finland, Europe), NF1 (H. B.Fuller, St. Paul, Minn., USA), and SOKALAN (BASF, Ludwigshafen, Germany,Europe). With respect to SOKALAN, this is a watersoluble polyacryliccopolymer of acrylic acid and maleic acid, having a molecular weight ofapproximately 4000. AQUASET- 529 is a composition containing polyacrylicacid cross-linked with glycerol, also containing sodium hypophosphite asa catalyst. CRITERION 2000 is an acidic solution of a partial salt ofpolyacrylic acid, having a molecular weight of approximately 2000. Withrespect to NF1, this is a copolymer containing carboxylic acidfunctionality and hydroxy functionality, as well as units with neitherfunctionality; NF1 also contains chain transfer agents, such as sodiumhypophosphite or organophosphate catalysts.

Further, compositions including polymeric polycarboxylic acids are alsocontemplated to be useful in preparing the binders described herein,such as those compositions described in U.S. Pat. Nos. 5,318,990,5,661,213, 6,136,916, and 6,331,350, the disclosures of which are herebyincorporated herein by reference. In particular, in U.S. Pat. Nos.5,318,990 and 6,331,350 an aqueous solution of a polymericpolycarboxylic acid, a polyol, and a catalyst is described.

As described in U.S. Pat. Nos. 5,318,990 and 6,331,350, the polymericpolycarboxylic acid comprises an organic polymer or oligomer containingmore than one pendant carboxy group. The polymeric polycarboxylic acidmay be a homopolymer or copolymer prepared from unsaturated carboxylicacids including, but not necessarily limited to, acrylic acid,methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamicacid, 2-methylmaleic acid, itaconic acid, 2-methylitaconic acid,α,β-methyleneglutaric acid, and the like. Alternatively, the polymericpolycarboxylic acid may be prepared from unsaturated anhydridesincluding, but not necessarily limited to, maleic anhydride, itaconicanhydride, acrylic anhydride, methacrylic anhydride, and the like, aswell as mixtures thereof. Methods for polymerizing these acids andanhydrides are well-known in the chemical art. The polymericpolycarboxylic acid may additionally comprise a copolymer of one or moreof the aforementioned unsaturated carboxylic acids or anhydrides and oneor more vinyl compounds including, but not necessarily limited to,styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, methylacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, methylmethacrylate, n-butyl methacrylate, isobutyl methacrylate, glycidylmethacrylate, vinyl methyl ether, vinyl acetate, and the like. Methodsfor preparing these copolymers are well-known in the art. The polymericpolycarboxylic acids may comprise homopolymers and copolymers ofpolyacrylic acid. The molecular weight of the polymeric polycarboxylicacid, and in particular polyacrylic acid polymer, may be is less than10000, less than 5000, or about 3000 or less. For example, the molecularweight may be 2000.

As described in U.S. Pat. Nos. 5,318,990 and 6,331,350, the polyol (in acomposition including a polymeric polycarboxylic acid) contains at leasttwo hydroxyl groups. The polyol should be sufficiently nonvolatile suchthat it will substantially remain available for reaction with thepolymeric polycarboxylic acid in the composition during heating andcuring operations. The polyol may be a compound with a molecular weightless than about 1000 bearing at least two hydroxyl groups such as,ethylene glycol, glycerol, pentaerythritol, trimethylol propane,sorbitol, sucrose, glucose, resorcinol, catechol, pyrogallol,glycollated ureas, 1,4-cyclohexane diol, diethanolamine,triethanolamine, and certain reactive polyols, for example,[beta]-hydroxyalkylamides such as, for example,bis(N,N-di(β-hydroxyethyl))adipamide, or it may be an addition polymercontaining at least two hydroxyl groups such as, polyvinyl alcohol,partially hydrolyzed polyvinyl acetate, and homopolymers or copolymersof hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and thelike.

As described in U.S. Pat. Nos. 5,318,990 and 6,331,350, the catalyst (ina composition including a polymeric polycarboxylic acid) is aphosphorous-containing accelerator which may be a compound with amolecular weight less than about 1000 such as, an alkali metalpolyphosphate, an alkali metal dihydrogen phosphate, a polyphosphoricacid, and an alkyl phosphinic acid or it may be an oligomer or polymerbearing phosphorous-containing groups, for example, addition polymers ofacrylic and/or maleic acids formed in the presence of sodiumhypophosphite, addition polymers prepared from ethylenically unsaturatedmonomers in the presence of phosphorous salt chain transfer agents orterminators, and addition polymers containing acid-functional monomerresidues, for example, copolymerized phosphoethyl methacrylate, and likephosphonic acid esters, and copolymerized vinyl sulfonic acid monomers,and their salts. The phosphorous-containing accelerator may be used at alevel of from about 1% to about 40%, by weight based on the combinedweight of the polymeric polycarboxylic acid and the polyol. A level ofphosphorous containing accelerator of from about 2.5% to about 10%, byweight based on the combined weight of the polymeric polycarboxylic acidand the polyol may be used. Examples of such catalysts include, but arenot limited to, sodium hypophosphite, sodium phosphite, potassiumphosphite, disodium pyrophosphate, tetrasodium pyrophosphate, sodiumtripolyphosphate, sodium hexametaphosphate, potassium phosphate,potassium polymetaphosphate, potassium polyphosphate, potassiumtripolyphosphate, sodium trimeta phosphate, and sodium tetrametaphosphate, as well as mixtures thereof. Compositions including polymericpolycarboxylic acids described in U.S. Pat. Nos. 5,661,213 and 6,136,916that are contemplated to be useful in preparing the binders describedherein comprise an aqueous solution of a polymeric polycarboxylic acid,a polyol containing at least two hydroxyl groups, and aphosphorous-containing accelerator, wherein the ratio of the number ofequivalents of carboxylic acid groups, to the number of equivalents ofhydroxyl groups is from about 1:0.01 to about 1:3.

As disclosed in U.S. Pat. Nos. 5,661,213 and 6,136,916, the polymericpolycarboxylic acid may be, a polyester containing at least twocarboxylic acid groups or an addition polymer or oligomer containing atleast two copolymerized carboxylic acid-functional monomers. Thepolymeric polycarboxylic acid is preferably an addition polymer formedfrom at least one ethylenically unsaturated monomer. The additionpolymer may be in the form of a solution of the addition polymer in anaqueous medium such as, an alkali-soluble resin which has beensolubilized in a basic medium; in the form of an aqueous dispersion, forexample, an emulsion-polymerized dispersion; or in the form of anaqueous suspension. The addition polymer must contain at least twocarboxylic acid groups, anhydride groups, or salts thereof.Ethylenically unsaturated carboxylic acids such as, methacrylic acid,acrylic acid, crotonic acid, fumaric acid, maleic acid, 2-methyl maleicacid, itaconic acid, 2-methyl itaconic acid, α,(β-methylene glutaricacid, monoalkyl maleates, and monoalkyl fumarates; ethylenicallyunsaturated anhydrides, for example, maleic anhydride, itaconicanhydride, acrylic anhydride, and methacrylic anhydride; and saltsthereof, at a level of from about 1% to 100%, by weight, based on theweight of the addition polymer, may be used. Additional ethylenicallyunsaturated monomer may include acrylic ester monomers including methylacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decylacrylate, methyl methacrylate, butyl methacrylate, isodecylmethacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, andhydroxypropyl methacrylate; acrylamide or substituted acrylamides;styrene or substituted styrenes; butadiene; vinyl acetate or other vinylesters; acrylonitrile or methacrylonitrile; and the like. The additionpolymer containing at least two carboxylic acid groups, anhydridegroups, or salts thereof may have a molecular weight from about 300 toabout 10,000,000. A molecular weight from about 1000 to about 250,000may be used. When the addition polymer is an alkali-soluble resin havinga carboxylic acid, anhydride, or salt thereof, content of from about 5%to about 30%, by weight based on the total weight of the additionpolymer, a molecular weight from about 10,000 to about 100,000 may beutilized Methods for preparing these additional polymers are well-knownin the art.

As described in U.S. Pat. Nos. 5,661,213 and 6,136,916, the polyol (in acomposition including a polymeric polycarboxylic acid) contains at leasttwo hydroxyl groups and should be sufficiently nonvolatile that itremains substantially available for reaction with the polymericpolycarboxylic acid in the composition during heating and curingoperations. The polyol may be a compound with a molecular weight lessthan about 1000 bearing at least two hydroxyl groups, for example,ethylene glycol, glycerol, pentaerythritol, trimethylol propane,sorbitol, sucrose, glucose, resorcinol, catechol, pyrogallol,glycollated ureas, 1,4-cyclohexane diol, diethanolamine,triethanolamine, and certain reactive polyols, for example,[beta]-hydroxyalkylamides, for example, bis(N,N-di(β-hydroxyethyl))adipamide, bis(N,N-di(β-hydroxypropyl)) azelamide,bis(N,N-di(β-hydroxypropyl)) adipamide, bis(N,N-di(β-hydroxypropyl))glutaramide, bis(N,N-di(β-hydroxypropyl)) succinamide, andbis(N-methyl-N-((β-hydroxyethyl)) oxamide, or it may be an additionpolymer containing at least two hydroxyl groups such as, polyvinylalcohol, partially hydrolyzed polyvinyl acetate, and homopolymers orcopolymers of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate,and the like.

As described in U.S. Pat. Nos. 5,661,213 and 6,136,916, thephosphorous-containing accelerator (in a composition including apolymeric polycarboxylic acid) may be a compound with a molecular weightless than about 1000 such as, an alkali metal hypophosphite salt, analkali metal phosphite, an alkali metal polyphosphate, an alkali metaldihydrogen phosphate, a polyphosphoric acid, and an alkyl phosphinicacid or it may be an oligomer or polymer bearing phosphorous-containinggroups such as, addition polymers of acrylic and/or maleic acids formedin the presence of sodium hypophosphite, addition polymers prepared fromethylenically unsaturated monomers in the presence of phosphorous saltchain transfer agents or terminators, and addition polymers containingacid-functional monomer residues such as, copolymerized phosphoethylmethacrylate, and like phosphonic acid esters, and copolymerized vinylsulfonic acid monomers, and their salts. The phosphorous-containingaccelerator may be used at a level of from about 1% to about 40%, byweight based on the combined weight of the polyacid and the polyol. Alevel of phosphorous-containing accelerator of from about 2.5% to about10%, by weight based on the combined weight of the polyacid and thepolyol, may be utilized.

As used herein, the term “amine base” includes, but is not limited to,ammonia, a primary amine, i.e., NH₂R¹, and a secondary amine, i.e.,NHR¹R², where R¹ and R² are each independently selected in NHR¹R², andwhere R¹ and R² are selected from alkyl, cycloalkyl, alkenyl,cycloalkenyl, heterocyclyl , aryl, and heteroaryl, as defined herein.Illustratively, the amine base may be substantially volatile orsubstantially non-volatile under conditions sufficient to promoteformation of the thermoset binder during thermal curing. Illustratively,the amine base may be a substantially volatile base, such as, ammonia,ethylamine, diethylamine, dimethylamine, and ethylpropylamine.Alternatively, the amine base may be a substantially non-volatile base,for example, aniline, 1-naphthylamine, 2-naphthylamine, andpara-aminophenol.

As used herein, “reducing sugar” indicates one or more sugars thatcontain aldehyde groups, or that can isomerize, i.e., tautomerize, tocontain aldehyde groups, which groups are reactive with an amino groupunder Maillard reaction conditions and which groups may be oxidizedwith, for example, Cu⁺² to afford carboxylic acids. It is alsoappreciated that any such carbohydrate reactant may be optionallysubstituted, such as with hydroxy, halo, alkyl, alkoxy, and the like. Itis further appreciated that in any such carbohydrate reactant, one ormore chiral centers are present, and that both possible optical isomersat each chiral center are contemplated to be included in the inventiondescribed herein. Further, it is also to be understood that variousmixtures, including racemic mixtures, or other diastereomeric mixturesof the various optical isomers of any such carbohydrate reactant, aswell as various geometric isomers thereof, may be used in one or moreembodiments described herein.

FIG. 7 shows examples of reactants for a Maillard reaction. Examples ofamine reactants include proteins, peptides, amino acids, ammonium saltsof polymeric polycarboxylic acids, and ammonium salts of monomericpolycarboxylic acids. As illustrated, ammonium can be [⁺NH₄]_(x),[⁺NH₃R¹]_(x) and [⁺NH₂R¹R²]_(x), where x is at least about 1. Withrespect to ⁺NH₂R¹R², R¹ and R² are each independently selected.Moreover, R¹ and R² are selected from alkyl, cycloalkyl, alkenyl,cycloalkenyl, heterocyclyl, aryl, and heteroaryl, as described above.FIG. 7 also illustrates examples of reducing-sugar reactants forproducing melanoidins, including monosaccharides, in their aldose orketose form, polysaccharides, or combinations thereof. Illustrativenon-carbohydrate carbonyl reactants for producing melanoidins are alsoshown in FIG. 7 and include various aldehydes, e.g., pyruvaldehyde andfurfural, as well as compounds such as ascorbic acid and quinone.

FIG. 8 shows a schematic of a Maillard reaction, which culminates in theproduction of melanoidins. In its initial phase, a Maillard reactioninvolves a carbohydrate reactant, for example, a reducing sugar (notethat the carbohydrate reactant may come from a substance capable ofproducing a reducing sugar under Maillard reaction conditions). Thereaction also involves condensing the carbohydrate reactant (e.g.,reducing sugar) with an amine reactant, i.e., a compound possessing anamino group. In other words, the carbohydrate reactant and the aminereactant are the melanoidin reactants for a Maillard reaction. Thecondensation of these two constituents produces an N-substitutedglycosylamine. For a more detailed description of the Maillard reactionsee, Hodge, J. E. Chemistry of Browning Reactions in Model Systems J.Agric. Food Chem. 1953, 1, 928-943, the disclosure of which is herebyincorporated herein by reference. The compound possessing a free aminogroup in a Maillard reaction may be present in the form of an aminoacid. The free amino group can also come from a protein where the freeamino groups are available in the form of, for example, the α-aminogroup of lysine residues, and/or the ϵ-amino group of the terminal aminoacid.

Another aspect of conducting a Maillard reaction as described herein isthat, initially, the aqueous Maillard reactant solution (which also is abinder), as described above, has an alkaline pH. However, once thesolution is disposed on a collection of non or loosely assembled matter,and curing is initiated, the pH decreases (i.e., the binder becomesacidic). It should be understood that when fabricating a material, theamount of contact between the binder and components of machinery used inthe fabrication is greater prior to curing, (i.e., when the bindersolution is alkaline) as compared to after the binder is cured (i.e.,when the binder is acidic). An alkaline composition is less corrosivethan an acidic composition. Accordingly, corrosivity of the fabricationprocess is decreased.

It should be appreciated that by using the aqueous Maillard reactantsolution described herein, the machinery used to fabricate fiberglass isnot exposed as much to an acidic solution because, as described above,the pH of the Maillard reactant solution is alkaline. Furthermore,during the fabrication the only time an acidic condition develops isafter the binder has been applied to fibers. Once the binder is appliedto the fibers, the binder and the material that incorporates the binder,has relatively infrequent contacts with the components of the machineryas compared to the time prior to applying the binder to the fibers.Accordingly, corrosivity of fiberglass fabrication (and the fabricationof other materials) is decreased.

Without being bound to theory, covalent reaction of the polycarboxylicacid ammonium salt and reducing sugar reactants of a Maillard reaction,which as described herein occurs substantially during thermal curing toproduce brown-colored nitrogenous polymeric and co-polymeric melanoidinsof varying structure, is thought to involve initial Maillard reaction ofammonia with the aldehyde moiety of a reducing-sugar carbohydratereactant to afford N-substituted glycosylamine, as shown in FIG. 8 .Consumption of ammonia in such a way, with ammonia and a reducing sugarcarbohydrate reactant combination functioning as a latent acid catalyst,would be expected to result in a decrease in pH, which decrease isbelieved to promote esterification processes and/or dehydration of thepolycarboxylic acid to afford its corresponding anhydride derivative. AtpH <7, the Amadori rearrangement product of N-substituted glycosylamine,i.e., 1-amino-1-deoxy-2-ketose, would be expected to undergo mainly1,2-enolization with the formation of furfural when, for example,pentoses are involved, or hydroxymethylfurfural when, for example,hexoses are involved, as a prelude to melanoidin production.Concurrently, contemporaneously, or sequentially with the production ofmelanoidins, esterification processes may occur involving melanoidins,polycarboxylic acid and/or its corresponding anhydride derivative, andresidual carbohydrate, which processes lead to extensive cross-linking.Accompanied by sugar dehydration reactions, whereupon conjugated doublebonds are produced that may undergo polymerization, a water-resistantthermoset binder is produced consisting of polyester adductsinterconnected by a network of carbon carbon single bonds. Consistentwith the above reaction scenario is a strong absorbance near 1734 cm⁻¹in the FT-IR spectrum of a cured binder described herein, whichabsorbance is within the 1750-1730 cm⁻¹ range expected for estercarbonyl C—O vibrations.

The following discussion is directed to (i) examples of carbohydrate andamine reactants, which can be used in a Maillard reaction and (ii) howthese reactants can be combined. First, it should be understood that anycarbohydrate and/or compound possessing a primary or secondary aminogroup, that will act as a reactant in a Maillard reaction, can beutilized in the binders of the present invention. Such compounds can beidentified and utilized by one of ordinary skill in the art with theguidelines disclosed herein.

With respect to exemplary reactants, it should also be appreciated thatusing an ammonium salt of a polycarboxylic acid as an amine reactant isan effective reactant in a Maillard reaction. Ammonium salts ofpolycarboxylic acids can be generated by neutralizing the acid groupswith an amine base, thereby producing polycarboxylic acid ammonium saltgroups. Complete neutralization, i.e., about 100% calculated on anequivalents basis, may eliminate any need to titrate or partiallyneutralize acid groups in the polycarboxylic acid(s) prior to binderformation. However, it is expected that less-than-completeneutralization would not inhibit formation of the binder. Note thatneutralization of the acid groups of the polycarboxylic acid(s) may becarried out either before or after the polycarboxylic acid(s) is mixedwith the carbohydrate(s).

With respect to the carbohydrate reactant, it may include one or morereactants having one or more reducing sugars. In one aspect, anycarbohydrate reactant should be sufficiently nonvolatile to maximize itsability to remain available for reaction with the polycarboxylic acidammonium salt reactant. The carbohydrate reactant may be amonosaccharide in its aldose or ketose form, including a triose, atetrose, a pentose, a hexose, or a heptose; or a polysaccharide; orcombinations thereof. A carbohydrate reactant may be a reducing sugar,or one that yields one or more reducing sugars in situ under thermalcuring conditions. For example, when a triose serves as the carbohydratereactant, or is used in combination with other reducing sugars and/or apolysaccharide, an aldotriose sugar or a ketotriose sugar may beutilized, such as glyceraldehyde and dihydroxyacetone, respectively.When a tetrose serves as the carbohydrate reactant, or is used incombination with other reducing sugars and/or a polysaccharide,aldotetrose sugars, such as erythrose and threose; and ketotetrosesugars, such as erythrulose, may be utilized. When a pentose serves asthe carbohydrate reactant, or is used in combination with other reducingsugars and/or a polysaccharide, aldopentose sugars, such as ribose,arabinose, xylose, and lyxose; and ketopentose sugars, such as ribulose,arabulose, xylulose, and lyxulose, may be utilized. When a hexose servesas the carbohydrate reactant, or is used in combination with otherreducing sugars and/or a polysaccharide, aldohexose sugars, such asglucose (i.e., dextrose), m an nose, galactose, allose, altrose, talose,gulose, and idose; and ketohexose sugars, such as f ructose, psicose,sorbose and tagatose, may be utilized. When a heptose serves as thecarbohydrate reactant, or is used in combination with other reducingsugars and/or a polysaccharide, a ketoheptose sugar such assedoheptulose may be utilized. Other stereoisomers of such carbohydratereactants not known to occur naturally are also contemplated to beuseful in preparing the binder compositions as described herein. When apolysaccharide serves as the carbohydrate, or is used in combinationwith monosaccharides, sucrose, lactose, maltose, starch, and cellulosemay be utilized.

Furthermore, the carbohydrate reactant in the Maillard reaction may beused in combination with a non-carbohydrate polyhydroxy reactant.Examples of non-carbohydrate polyhydroxy reactants which can be used incombination with the carbohydrate reactant include, but are not limitedto, trimethylolpropane, glycerol, pentaerythritol, polyvinyl alcohol,partially hydrolyzed polyvinyl acetate, fully hydrolyzed polyvinylacetate, and mixtures thereof. In one aspect, the non : carbohydratepolyhydroxy reactant is sufficiently nonvolatile to maximize its abilityto remain available for reaction with a monomeric or polymericpolycarboxylic acid reactant. It is appreciated that the hydrophobicityof the non-carbohydrate polyhydroxy reactant may be a factor indetermining the physical properties of a binder prepared as describedherein.

When a partially hydrolyzed polyvinyl acetate serves as anon-carbohydrate polyhydroxy reactant, a commercially available compoundsuch as an 87-89% hydrolyzed polyvinyl acetate may be utilized, such as,DuPont ELVANOL 51-05. DuPont ELVANOL 51-05 has a molecular weight ofabout 22,000-26,000 Da and a viscosity of about 5.0-6.0 centipoises.Other partially hydrolyzed polyvinyl acetates contemplated to be usefulin preparing binder compositions as described herein include, but arenot limited to, 87-89% hydrolyzed polyvinyl acetates differing inmolecular weight and viscosity from ELVANOL 51-05, such as, for example,DuPont ELVANOL 51-04, ELVANOL 51-08, ELVANOL 50-14, ELVANOL 52-22,ELVANOL 50-26, ELVANOL 50-42; and partially hydrolyzed polyvinylacetates differing in molecular weight, viscosity, and/or degree ofhydrolysis from ELVANOL 51-05, such as, DuPont ELVANOL 51-03 (86-89%hydrolyzed), ELVANOL 70-14 (95.0-97.0% hydrolyzed), ELVANOL 70-27(95.5-96.5% hydrolyzed), ELVANOL 60-30 (90-93% hydrolyzed). Otherpartially hydrolyzed polyvinyl acetates contemplated to be useful inpreparing binder compositions as described herein include, but are notlimited to, Clariant MOWIOL 15-79, MOWIOL 3-83, MOWIOL 4-88, MOWIOL5-88, MOWIOL 8-88, MOWIOL 18-88, MOWIOL 23-88, MOWIOL 26-88, MOWIOL40-88, MOWIOL 47-88, and MOWIOL 30-92, as well as Celanese CELVOL 203,CELVOL 205, CELVOL 502, 5 CELVOL 504, CELVOL 513, CELVOL 523, CELVOL523TV, CELVOL 530, CELVOL 540, CELVOL 540TV, CELVOL 418, CELVOL 425, andCELVOL 443. Also contemplated to be useful are similar or analogouspartially hydrolyzed polyvinyl acetates available from other commercialsuppliers.

When a fully hydrolyzed polyvinyl acetate serves as a non-carbohydratepolyhydroxy reactant, Clariant MOWIOL 4-98, having a molecular weight ofabout 27,000 Da, may be utilized. Other fully hydrolyzed polyvinylacetates contemplated to be useful include, but are not limited to,DuPont ELVANOL 70-03 (98.0-98.8% hydrolyzed), ELVANOL 70-04 (98.0-98.8%hydrolyzed), ELVANOL 70-06 (98.5-99.2% hydrolyzed), ELVANOL 90-50(99.0-99.8% hydrolyzed), ELVANOL 70-20 (98.5-99.2% hydrolyzed), ELVANOL70-30 (98.5- 99.2% hydrolyzed), ELVANOL 71-30 (99.0-99.8% hydrolyzed),ELVANOL 70-62 (98.4-99.8% hydrolyzed), ELVANOL 70-63 (98.5-99.2%hydrolyzed), ELVANOL 70-75 (98.5-99.2% hydrolyzed), Clariant MOWIOL3-98, MOWIOL 6-98, MOWIOL 10-98, MOWIOL 20-98, MOWIOL 56-98, MOWIOL28-99, and Celanese CELVOL 103, CELVOL107, CELVOL 305, CELVOL 310,CELVOL 325, CELVOL 325LA, and CELVOL 350, as well as similar oranalogous fully hydrolyzed polyvinyl acetates from other commercialsuppliers.

The aforementioned Maillard reactants may be combined to make an aqueouscomposition that includes a carbohydrate reactant and an amine reactant.These aqueous binders represent examples of uncured binders. Asdiscussed below, these aqueous compositions can be used as binders ofthe present invention. These binders are formaldehyde-free, curable,alkaline, aqueous binder compositions. Furthermore, as indicated above,the carbohydrate reactant of the Maillard reactants may be used incombination with a non-carbohydrate polyhydroxy reactant. Accordingly,any time the carbohydrate reactant is mentioned it should be understoodthat it can be used in combination with a non-carbohydrate polyhydroxyreactant.

In one illustrative embodiment, the aqueous solution of Maillardreactants may include (i) an ammonium salt of one or more polycarboxylicacid reactants and (ii) one or more carbohydrate reactants having areducing sugar. The pH of this solution prior to placing it in contactwith the material to be bound can be greater than or equal to about 7.In addition, this solution can have a pH of less than or equal to about10. The ratio of the number of moles of the polycarboxylic acidreactant(s) to the number of moles of the carbohydrate reactant(s) canbe in the range from about 1:4 to about 1:15. In one example, the ratioof the number of moles of the polycarboxylic acid reactant(s) to thenumber of moles of the carbohydrate reactant(s) in the bindercomposition is about 1:5. In another example, the ratio of the number ofmoles of the polycarboxylic acid reactant(s) to the number of moles ofthe carbohydrate reactant(s) is about 1:6. In yet another example, theratio of the number of moles of the polycarboxylic acid reactant(s) tothe number of moles of the carbohydrate reactant(s) is about 1:7.

As described above, the aqueous binder composition includes (i) anammonium salt of one or more polycarboxylic acid reactants and (ii) oneor more carbohydrate reactants having a reducing sugar. It should beappreciated that when an ammonium salt of a monomeric or a polymericpolycarboxylic acid is used as an amine reactant, the molar equivalentsof ammonium ion may or may not be equal to the molar equivalents of acidsalt groups present on the polycarboxylic acid. In one illustrativeexample, an ammonium salt may be monobasic, dibasic, or tribasic when atricarboxylic acid is used as a polycarboxylic acid reactant. Thus, themolar equivalents of the ammonium ion may be present in an amount lessthan or about equal to the molar equivalents of acid salt groups presentin a polycarboxylic acid. Accordingly, the salt can be monobasic ordibasic when the polycarboxylic acid reactant is a dicarboxylic acid.Further, the molar equivalents of ammonium ion may be present in anamount less than, or about equal to, the molar equivalents of acid saltgroups present in a polymeric polycarboxylic acid, and so on and soforth. When a monobasic salt of a dicarboxylic acid is used, or when adibasic salt of a tricarboxylic acid is used, or when the molarequivalents of ammonium ions are present in an amount less than themolar equivalents of acid salt groups present in a polymericpolycarboxylic acid, the pH of the binder composition may requireadjustment to achieve alkalinity.

The uncured, formaldehyde-free, thermally-curable, alkaline, aqueousbinder composition can be used to fabricate a number of differentmaterials. In particular, these binders can be used to produce orpromote cohesion in non or loosely assembled matter by placing thebinder in contact with the matter to be bound. Any number of well knowntechniques can be employed to place the aqueous binder in contact withthe material to be bound. For example, the aqueous binder can be sprayedon (for example during the binding glass fibers) or applied via aroll-coat apparatus. These aqueous binders can be applied to a mat ofglass fibers (e.g., sprayed onto the mat), during production offiberglass insulation products. Once the aqueous binder is in contactwith the glass fibers the residual heat from the glass fibers (note thatthe glass fibers are made from molten glass and thus contain residualheat) and the flow of air through the fibrous mat will evaporate (i.e.,remove) water from the binder. Removing the water leaves the remainingcomponents of the binder on the fibers as a coating of viscous orsemi-viscous high-solids liquid. This coating of viscous or semi-viscoushigh-solids liquid functions as a binder. At this point, the mat has notbeen cured. In other words, the uncured binder functions to bind theglass fibers in the mat.

Furthermore, it should be understood that the above described aqueousbinders can be cured. For example, any of the above described aqueousbinders can be disposed (e.g., sprayed) on the material to be bound, andthen heated. For example, in the case of making fiberglass insulationproducts, after the aqueous binder has been applied to the mat, thebinder coated mat is transferred to a curing oven. In the curing oventhe mat is heated (e.g., from about 300° F. to about 600° F.) and thebinder cured. The cured binder is a formaldehyde-free, water-resistantthermoset binder that attaches the glass fibers of the mat together.Note that the drying and thermal curing may occur either sequentially,contemporaneously, or concurrently.

With respect to making binders that are water-insoluble when cured, itshould be appreciated that the ratio of the number of molar equivalentsof acid salt groups present on the polycarboxylic acid reactant(s) tothe number of molar equivalents of hydroxyl groups present on thecarbohydrate reactant(s) may be in the range from about 0.04:1 to about0.15:1. After curing, these formulations result in a water-resistantthermoset binder. In one variation, the number of molar equivalents ofhydroxyl groups present on the carbohydrate reactant(s) is about twentyfive-fold greater than the number of molar equivalents of acid saltgroups present on the polycarboxylic acid reactant(s). In anothervariation, the number of molar equivalents of hydroxyl groups present onthe carbohydrate reactant(s) is about ten-fold greater than the numberof molar equivalents of acid salt groups present on the polycarboxylicacid reactant(s). In yet another variation, the number of molarequivalents of hydroxyl groups present on the carbohydrate reactant(s)is about sixfold greater than the number of molar equivalents of acidsalt groups present on the polycarboxylic acid reactant(s).

In other embodiments of the invention, a binder that is already curedcan disposed on a material to be bound. As indicated above, most curedbinders will typically contain water-insoluble melanoidins. Accordingly,these binders will also be water-resistant thermoset binders.

As discussed below, various additives can be incorporated into thebinder composition. These additives give the binders of the presentinvention additional desirable characteristics. For example, the bindermay include a silicon-containing coupling agent. Many silicon-containingcoupling agents are commercially available from the Dow-CorningCorporation, Petrarch Systems, and by the General Electric Company.Illustratively, the silicon-containing coupling agent includes compoundssuch as silylethers and alkylsilyl ethers, each of which may beoptionally substituted, such as with halogen, alkoxy, amino, and thelike. In one variation, the silicon-containing compound is anamino-substituted silane, such as, gamma-aminopropyltriethoxy silane(General Electric Silicones, SILQUEST A-1101; Wilton, Conn.; USA). Inanother variation, the silicon-containing compound is anamino-substituted silane, for example, aminoethylaminopropyltrimethoxysilane (Dow Z-6020; Dow Chemical, Midland, Mich.; USA). In anothervariation, the silicon-containing compound isgamma-glycidoxypropyltrimethoxysilane (General Electric Silicones,SILQUEST A-187). In yet another variation, the silicon-containingcompound is an n-propylamine silane (Creanova (formerly Huls America)HYDROSIL 2627; Creanova; Somerset, N.J.; U.S.A.).

The silicon-containing coupling agents are typically present in thebinder in the range from about percent to about 1 percent by weightbased upon the dissolved binder solids (i.e., about 0.1 percent to about1 percent based upon the weight of the solids added to the aqueoussolution). In one application, one or more of these silicon-containingcompounds can be added to the aqueous uncured binder. The binder is thenapplied to the material to be bound. Thereafter, the binder may be curedif desired. These silicone containing compounds enhance the ability ofthe binder to adhere to the matter the binder is disposed on, such asglass fibers. Enhancing the binder.s ability to adhere to the matterimproves, for example, its ability to produce or promote cohesion in nonor loosely assembled substance(s).

A binder that includes a silicone containing coupling agent can beprepared by admixing about 10 to about 50 weight percent aqueoussolution of one or more polycarboxylic acid reactants, alreadyneutralized with an amine base or neutralized in situ, with about 10-50weight percent aqueous solution of one or more carbohydrate reactantshaving reducing sugar, and an effective amount of a silicon containingcoupling agent. In one variation, one or more polycarboxylic acidreactants and one or more carbohydrate reactants, the latter havingreducing sugar, may be combined as solids, mixed with water, and themixture then treated with aqueous amine base (to neutralize the one ormore polycarboxylic acid reactants) and a silicon-containing couplingagent to generate an aqueous solution 10-50 weight percent in eachpolycarboxylic acid reactant and each carbohydrate reactant.

In another illustrative embodiment, a binder of the present inventionmay include one or more corrosion inhibitors. These corrosion inhibitorsprevent or inhibit the eating or wearing away of a substance, such as,metal caused by chemical decomposition brought about by an acid. When acorrosion inhibitor is included in a binder of the present invention,the binder's corrosivity is decreased as compared to the corrosivity ofthe binder without the inhibitor present. In one embodiment, thesecorrosion inhibitors can be utilized to decrease the corrosivity of theglass fiber containing compositions described herein. Illustratively,corrosion inhibitors include one or more of the following, a dedustingoil, or a monoammonium phosphate, sodium metasilicate pentahydrate,melamine, tin(II)oxalate, and/or methyl hydrogen silicone fluidemulsion. When included in a binder of the present invention, corrosioninhibitors are typically present in the binder in the range from about0.5 percent to about 2 percent by weight based upon the dissolved bindersolids.

By following the disclosed guidelines, one of ordinary skill in the artwill be able to vary the concentrations of the reactants of the aqueousbinder to produce a wide range of binder compositions. In particular,aqueous binder compositions can be formulated to have an alkaline pH.For example, a pH in the range from greater than or equal to about 7 toless than or equal to about 10. Examples of the binder reactants thatcan be manipulated include (i) the polycarboxylic acid reactant(s), (ii)the amine base, (iii) the carbohydrate reactant(s), (iv) thesilicon-containing coupling agent, and (v) the corrosion inhibitorcompounds. Having the pH of the aqueous binders (e.g. uncured binders)of the present invention in the alkaline range inhibits the corrosion ofmaterials the binder comes in contact with, such as machines used in themanufacturing process (e.g., in manufacturing fiberglass). Note this isespecially true when the corrosivity of acidic binders is compared tobinders of the present invention. Accordingly, the life span of themachinery increases while the cost of maintaining these machinesdecreases.

Furthermore, standard equipment can be used with the binders of thepresent invention, rather than having to utilize relatively corrosiveresistant machine components that come into contact with acidic binders,such as stainless steel components. Therefore, the binders disclosedherein decrease the cost of manufacturing bound materials.

1. A composite wood board comprising wood particles and an organicbinder.
 2. A composite wood board in accordance with claim 1, in whichthe binder which is substantially formaldehyde free, preferablyformaldehyde free. 3-20. (canceled)